1. Field of the Invention
The present invention relates to a profile producing method and a profile producing apparatus for producing a profile using a color chart and a profile producing program storage medium storing a profile producing program which causes a computer to operate as the profile producing apparatus when the profile producing program is incorporated into the computer.
2. Description of the Related Art
Hitherto, there is known a profile producing method and a profile producing apparatus for producing a profile defining an association between coordinates of a color space depending on a device such as a printer and a scanner for performing input and output of images and coordinates of a color space independent of the device, using a color chart in which color patches are arranged. For example, in a shop photographic print system in which an image of a photographic print is read by a scanner and fed to a computer in form of an original image, so that a copy of the original image is created on the computer and is outputted on the photographic print by a printer, the computer operates as the profile producing apparatus so that a profile suitable for the scanner and the printer is created in form of for example an LUT (Look Up Table). And a color conversion between the color space depending on the device and the color space independent of the device is applied to the original image in accordance with the profile, so that a color of the photographic print of the original is coincident with a color of the photographic print of the copy.
Hitherto, to create the profile, there are used a color chart referred to as IT8 for example and a lattice color chart in which color patches corresponding to lattice points on a predetermined lattice defined in a color space are arranged in a similar fashion to that of lattice points on the color space.
By the way, to create profiles suitable for devices such as a printer and a scanner, respectively, an image of a color chart is inputted and outputted by the associated device so that a profile is created in accordance with a color of the color chart thus inputted and outputted. Further, when an image is inputted and outputted by a device, generally, it involves a distortion of a color in an in-plane direction of the image and a fluctuation in color by a change with elapse. A high-performance device is small in such distortion and fluctuation, and a device, which is low in performance, is large in such distortion and fluctuation.
The above-mentioned distortion and fluctuation greatly have an effect on accuracy and continuity of the profile. For this reason, at the time of creation of the profile, it is desired to create the profile taking into consideration the performance of the device, which will cause the above-mentioned distortion and fluctuation, and those distortion and fluctuation, particularly the performance when the color chart is inputted and outputted by the device.